Lithium argyrodite@lithium titanium phosphate@reduced graphene oxide coated carbon cloth as energy storage and hydrogen evolution reaction electrodes

초록

Batteries and supercapacitors were popular energy storage devices, but their practical uses were limited by their low energy densities and batteries' moderate power densities. The supercapattery, an ultimate energy storage device, was a novel family of devices that combined the storage mechanisms of a supercapacitor and a battery. To overcome these challenges, we provided a unique LPSC/LTP/r-GO hybrid electrode material for supercapattery and hydrogen evolution reaction (HER) applications. The design integrates (i) ion-transport functionality from the argyrodite LPSC phase, (ii) a structurally robust Li-ion host/electroactive phosphate phase (LTP), and (iii) a percolating electronic network provided by r-GO, thereby enabling mixed ionic/electronic transport and improved interfacial charge transfer compared with single-phase electrodes. Lithium phosphorus sulfur chloride or Argyrodite (Li6PS5Cl), lithium titanium phosphate (LiTi2(PO4)3), and reduced graphene oxide (r-GO) were synthesized using the ball milling method, sol-gel method, and Hummer's method, respectively. It was discovered that the LPSC/LTP/r-GO had a specific capacity (Qs) of 1880.5593 C/g at an initial scan rate (5 mV/s) and 1895.6694 C/g at an initial current density (2 A/g), respectively, in a 3-electrode system. The LPSC/LTP/r-GO had Qs of 280 C/g and 272.98 C/g at 5mv/s and at 2 A/g, respectively, using by 2-electrode system. The computed coulombic efficiency was 97% with the capacity retention of 94%. The hybrid device shows the power density (Pd) and energy density (Ed) at 2 A/g were 3600 W kg-1 and 70 Wh kg-1, respectively. Furthermore, the material LPSC/LTP/r-GO demonstrated exceptional catalytic activity during HER application, exhibiting the lowest overpotential of 24 mV and a Tafel slope of 33 mV dec-1. From all the above findings of the composite material LPSC/LTP/r-GO proved an excellent choice in applications of energy storage devices.

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